okane_core/report/
balance.rs

1use std::collections::HashMap;
2
3use super::{
4    context::Account,
5    eval::{Amount, EvalError, PostingAmount},
6};
7
8/// Error related to [Balance] operations.
9#[derive(Debug, thiserror::Error, PartialEq, Eq)]
10pub enum BalanceError {
11    #[error("balance = 0 cannot deduce posting amount when balance has multi commodities")]
12    MultiCommodityWithPartialSet(#[from] EvalError),
13}
14
15/// Accumulated balance of accounts.
16#[derive(Debug, Default, PartialEq, Eq, Clone)]
17pub struct Balance<'ctx> {
18    accounts: HashMap<Account<'ctx>, Amount<'ctx>>,
19}
20
21impl<'ctx> FromIterator<(Account<'ctx>, Amount<'ctx>)> for Balance<'ctx> {
22    /// Constructs [Balance] instance out of Iterator.
23    fn from_iter<T>(iter: T) -> Self
24    where
25        T: IntoIterator<Item = (Account<'ctx>, Amount<'ctx>)>,
26    {
27        Self {
28            accounts: iter.into_iter().collect(),
29        }
30    }
31}
32
33impl<'ctx> Balance<'ctx> {
34    /// Adds a particular account value, and returns the updated balance.
35    pub fn add_amount(&mut self, account: Account<'ctx>, amount: Amount<'ctx>) -> &Amount<'ctx> {
36        let curr: &mut Amount = self.accounts.entry(account).or_default();
37        *curr += amount;
38        curr
39    }
40
41    /// Adds a particular account value with the specified commodity, and returns the updated balance.
42    pub fn add_posting_amount(
43        &mut self,
44        account: Account<'ctx>,
45        amount: PostingAmount<'ctx>,
46    ) -> &Amount<'ctx> {
47        let curr: &mut Amount = self.accounts.entry(account).or_default();
48        *curr += amount;
49        curr
50    }
51
52    /// Tries to set the particular account's balance with the specified commodity,
53    /// and returns the delta which should have caused the difference.
54    pub fn set_partial(
55        &mut self,
56        account: Account<'ctx>,
57        amount: PostingAmount<'ctx>,
58    ) -> Result<PostingAmount<'ctx>, BalanceError> {
59        match amount {
60            PostingAmount::Zero => {
61                let prev: Amount<'ctx> = self
62                    .accounts
63                    .insert(account, amount.into())
64                    .unwrap_or_default();
65                (&prev)
66                    .try_into()
67                    .map_err(BalanceError::MultiCommodityWithPartialSet)
68            }
69            PostingAmount::Single(single_amount) => {
70                let prev = self
71                    .accounts
72                    .entry(account)
73                    .or_default()
74                    .set_partial(single_amount);
75                Ok(PostingAmount::Single(prev))
76            }
77        }
78    }
79
80    /// Gets the balance of the given account.
81    pub fn get(&self, account: &Account<'ctx>) -> Option<&Amount<'ctx>> {
82        self.accounts.get(account)
83    }
84
85    /// Constructs sorted vec of account and commodity tuple.
86    pub fn into_vec(self) -> Vec<(Account<'ctx>, Amount<'ctx>)> {
87        let mut ret: Vec<(Account<'ctx>, Amount<'ctx>)> = self.accounts.into_iter().collect();
88        ret.sort_unstable_by_key(|(a, _)| a.as_str());
89        ret
90    }
91}
92
93#[cfg(test)]
94mod tests {
95    use super::*;
96
97    use bumpalo::Bump;
98    use pretty_assertions::assert_eq;
99    use rust_decimal_macros::dec;
100
101    use super::super::context::ReportContext;
102
103    #[test]
104    fn balance_gives_zero_amount_when_not_initalized() {
105        let arena = Bump::new();
106        let mut ctx = ReportContext::new(&arena);
107
108        let balance = Balance::default();
109        assert_eq!(balance.get(&ctx.accounts.ensure("Expenses")), None);
110    }
111
112    #[test]
113    fn test_balance_increment_adds_value() {
114        let arena = Bump::new();
115        let mut ctx = ReportContext::new(&arena);
116
117        let mut balance = Balance::default();
118        let updated = balance
119            .add_posting_amount(
120                ctx.accounts.ensure("Expenses"),
121                PostingAmount::from_value(dec!(1000), ctx.commodities.ensure("JPY")),
122            )
123            .clone();
124
125        assert_eq!(
126            updated,
127            Amount::from_value(dec!(1000), ctx.commodities.ensure("JPY"))
128        );
129        assert_eq!(
130            balance.get(&ctx.accounts.ensure("Expenses")),
131            Some(&updated)
132        );
133
134        let updated = balance
135            .add_posting_amount(
136                ctx.accounts.ensure("Expenses"),
137                PostingAmount::from_value(dec!(-1000), ctx.commodities.ensure("JPY")),
138            )
139            .clone();
140
141        assert_eq!(updated, Amount::zero());
142        assert_eq!(
143            balance.get(&ctx.accounts.ensure("Expenses")),
144            Some(&updated)
145        );
146    }
147
148    #[test]
149    fn test_balance_set_partial_from_absolute_zero() {
150        let arena = Bump::new();
151        let mut ctx = ReportContext::new(&arena);
152        let mut balance = Balance::default();
153
154        let prev = balance
155            .set_partial(
156                ctx.accounts.ensure("Expenses"),
157                PostingAmount::from_value(dec!(1000), ctx.commodities.ensure("JPY")),
158            )
159            .unwrap();
160
161        // Note it won't be PostingAmount::zero(),
162        // as set_partial is called with commodity amount.
163        assert_eq!(
164            prev,
165            PostingAmount::from_value(dec!(0), ctx.commodities.ensure("JPY"))
166        );
167        assert_eq!(
168            balance.get(&ctx.accounts.ensure("Expenses")),
169            Some(&Amount::from_value(
170                dec!(1000),
171                ctx.commodities.ensure("JPY")
172            ))
173        );
174    }
175
176    #[test]
177    fn test_balance_set_partial_hit_same_commodity() {
178        let arena = Bump::new();
179        let mut ctx = ReportContext::new(&arena);
180        let mut balance = Balance::default();
181        balance.add_posting_amount(
182            ctx.accounts.ensure("Expenses"),
183            PostingAmount::from_value(dec!(1000), ctx.commodities.ensure("JPY")),
184        );
185
186        let prev = balance
187            .set_partial(
188                ctx.accounts.ensure("Expenses"),
189                PostingAmount::from_value(dec!(-1000), ctx.commodities.ensure("JPY")),
190            )
191            .unwrap();
192
193        assert_eq!(
194            prev,
195            PostingAmount::from_value(dec!(1000), ctx.commodities.ensure("JPY"))
196        );
197        assert_eq!(
198            balance.get(&ctx.accounts.ensure("Expenses")),
199            Some(&Amount::from_value(
200                dec!(-1000),
201                ctx.commodities.ensure("JPY")
202            ))
203        );
204    }
205
206    #[test]
207    fn test_balance_set_partial_multi_commodities() {
208        let arena = Bump::new();
209        let mut ctx = ReportContext::new(&arena);
210        let mut balance = Balance::default();
211        balance.add_posting_amount(
212            ctx.accounts.ensure("Expenses"),
213            PostingAmount::from_value(dec!(1000), ctx.commodities.ensure("JPY")),
214        );
215        balance.add_posting_amount(
216            ctx.accounts.ensure("Expenses"),
217            PostingAmount::from_value(dec!(200), ctx.commodities.ensure("CHF")),
218        );
219
220        let prev = balance
221            .set_partial(
222                ctx.accounts.ensure("Expenses"),
223                PostingAmount::from_value(dec!(100), ctx.commodities.ensure("CHF")),
224            )
225            .unwrap();
226
227        assert_eq!(
228            prev,
229            PostingAmount::from_value(dec!(200), ctx.commodities.ensure("CHF"))
230        );
231        assert_eq!(
232            balance.get(&ctx.accounts.ensure("Expenses")),
233            Some(&Amount::from_values([
234                (dec!(1000), ctx.commodities.ensure("JPY")),
235                (dec!(100), ctx.commodities.ensure("CHF")),
236            ]))
237        );
238    }
239
240    #[test]
241    fn test_balance_set_partial_zero_on_zero() {
242        let arena = Bump::new();
243        let mut ctx = ReportContext::new(&arena);
244        let mut balance = Balance::default();
245
246        let prev = balance
247            .set_partial(ctx.accounts.ensure("Expenses"), PostingAmount::zero())
248            .unwrap();
249
250        assert_eq!(prev, PostingAmount::zero());
251        assert_eq!(
252            balance.get(&ctx.accounts.ensure("Expenses")),
253            Some(&Amount::zero())
254        );
255    }
256
257    #[test]
258    fn test_balance_set_partial_zero_on_single_commodity() {
259        let arena = Bump::new();
260        let mut ctx = ReportContext::new(&arena);
261        let mut balance = Balance::default();
262        balance.add_posting_amount(
263            ctx.accounts.ensure("Expenses"),
264            PostingAmount::from_value(dec!(1000), ctx.commodities.ensure("JPY")),
265        );
266
267        let prev = balance
268            .set_partial(ctx.accounts.ensure("Expenses"), PostingAmount::zero())
269            .unwrap();
270
271        assert_eq!(
272            prev,
273            PostingAmount::from_value(dec!(1000), ctx.commodities.ensure("JPY"))
274        );
275        assert_eq!(
276            balance.get(&ctx.accounts.ensure("Expenses")),
277            Some(&Amount::zero())
278        );
279    }
280
281    #[test]
282    fn test_balance_set_partial_zero_fails_on_multi_commodities() {
283        let arena = Bump::new();
284        let mut ctx = ReportContext::new(&arena);
285        let mut balance = Balance::default();
286        balance.add_posting_amount(
287            ctx.accounts.ensure("Expenses"),
288            PostingAmount::from_value(dec!(1000), ctx.commodities.ensure("JPY")),
289        );
290        balance.add_posting_amount(
291            ctx.accounts.ensure("Expenses"),
292            PostingAmount::from_value(dec!(200), ctx.commodities.ensure("CHF")),
293        );
294
295        let err = balance
296            .set_partial(ctx.accounts.ensure("Expenses"), PostingAmount::zero())
297            .unwrap_err();
298
299        assert_eq!(
300            err,
301            BalanceError::MultiCommodityWithPartialSet(EvalError::PostingAmountRequired)
302        );
303    }
304}
okane_core/report/balance.rs

okane_core/report/
balance.rs
